1. Field of the Invention
The present invention relates to a substrate transfer apparatus for and a substrate transfer method of transferring any of a variety of substrates such as a semiconductor wafer, a liquid-crystal-display-panel glass substrate, a plasma-display-panel glass substrate, an optical-disk substrate, a magnetic-disk substrate, a photomagnetic-disk substrate and the like.
2. Description of Related Art
A substrate processing apparatus for processing a substrate such as a semiconductor wafer, a liquid-crystal-display-panel glass substrate or the like, comprises a substrate processing unit and an indexer unit connected thereto. The substrate processing unit comprises, for example, a plurality of processing chambers and a main transfer robot to execute a substrate carrying-in/carrying-out operation for carrying an unprocessed substrate in a processing chamber and carrying out a processed substrate from the processing chamber. On the other hand, the indexer unit comprises a cassette placing unit in which a cassette capable of housing a plurality of substrates is housed, and an indexer robot which has access to the cassette placed on the cassette placing unit for carrying-in/carrying-out of a substrate and which also receives/transfers a substrate from/to the main transfer robot.
The indexer robot carries out one unprocessed substrate from the cassette placed in the cassette placing unit and transfers the unprocessed substrate to the main transfer robot. The main transfer robot carries the unprocessed substrate thus received from the indexer robot, in any of the processing chambers. On the other hand, the main transfer robot takes out the processed substrate from a processing chamber and transfers this processed substrate to the indexer robot. The indexer robot houses the processed substrate thus received from the main transfer robot, in the cassette placed in the cassette placing unit.
Transfer of a substrate between the indexer robot and the main transfer robot is conducted with a substrate holding hand of the indexer robot located in a predetermined substrate transfer position. For example, a substrate positioning member of the cylinder drive type is disposed in association with the substrate holding hand of the indexer robot. When this substrate positioning member is driven, the substrate is relatively moved on the substrate holding hand, thus enabling the substrate to be positioned at an accurate position on the substrate holding hand. After the substrate has been thus positioned, the substrate is transferred from the indexer robot to the main transfer robot. As a result, the main transfer robot can hold the substrate in a stable manner. Accordingly, without occurrence of defective transfer (falling of a substrate or the like), the substrate can be transferred between the main transfer robot and the indexer robot and between the main transfer robot and a processing chamber.
The substrate holding hand of the main transfer robot is provided on the top thereof with a substrate supporting member. This substrate supporting member has an arrangement that a tapering face for bringing down a substrate to a predetermined position is formed inside and that a horizontal face joined with the lower end of the tapering face holds the peripheral edge of the underside of the substrate. It is solely the substrate supporting member that positions the substrate on the substrate holding hand of the main transfer robot. No positioning operation is conducted for transfer of a processed substrate from the main transfer robot to the indexer robot.
In the arrangement above-mentioned, the substrate is positioned with the use of the substrate positioning member of the cylinder drive type. This makes the arrangement complicated to prevent the substrate processing apparatus from being reduced in cost. Further, there is required a step of moving the substrate positioning member by a cylinder mechanism to position the substrate. Accordingly, it takes time to transfer the substrate from the indexer robot to the main transfer robot, thus preventing the throughput from being improved.
Further, before transfer of the substrate from the main transfer robot to the indexer robot, no substrate positioning is conducted. Thus, a processed substrate cannot disadvantageously securely be transferred.
It is an object of the present invention to provide a substrate transfer apparatus and a substrate transfer method, each of which is capable of positioning a substrate on the substrate holding hand with a simple arrangement, thus enabling the production cost to be reduced.
It is another object of the present invention to provide a substrate transfer apparatus and a substrate transfer method, each of which is capable of quickly positioning a substrate on the substrate holding hand, thus enabling the throughput to be improved.
It is a further object of the present invention to provide a substrate transfer apparatus and a substrate transfer method, each of which is capable of previously positioning a substrate not only for transferring the substrate from a first substrate transfer mechanism to a second substrate transfer mechanism, but also for transferring the substrate from the second substrate transfer mechanism to the first substrate transfer mechanism, thus enabling the substrate to be securely transferred.
According to the present invention, a substrate transfer apparatus comprises: a first substrate transfer mechanism (IR) having a first substrate holding hand (11, 12) which is movable while holding a substrate (W); and a first positioning mechanism (71, 72) disposed, in the moving passage of a substrate held by the first substrate holding hand, independently from the first substrate transfer mechanism, and having a positioning contact portion for regulating the movement of a substrate such that the substrate is positioned at a predetermined position on the first substrate holding hand. This substrate transfer apparatus further comprises a second substrate transfer mechanism (CR) having a second substrate holding hand (21, 22) for receiving and transferring a substrate directly from and to the first substrate holding hand.
The alphabets and numerals in the parentheses above-mentioned refer to corresponding component elements in the embodiment to be discussed later. However, it is not meant that the present invention is limited to this embodiment.
According to the present invention, when the first substrate holding hand is moved, the substrate held thereby comes in contact with the positioning contact portion of the first positioning mechanism, resulting in a relative movement of the substrate on the first substrate holding hand. Thus, the substrate can be positioned on the first substrate holding hand.
Since the positioning contact portion can fixedly be disposed in the moving passage of the substrate held by the first substrate holding hand, a cylinder drive mechanism or the like is not required as conventionally done. This simplifies the substrate transfer apparatus in arrangement, enabling the production cost to be lowered. Further, positioning the substrate on the first substrate holding hand can be achieved only by moving the first substrate holding hand. This eliminates a step of driving the substrate positioning member with the use of a cylinder drive mechanism as conventionally done. Thus, the substrate can quickly be positioned. This increases the substrate transfer speed, resulting in improvement in the throughput of a substrate processing apparatus incorporating this substrate transfer apparatus.
Further, the substrate positioned on the first substrate holding hand can securely be transferred to the second substrate holding hand. Positioning the substrate on the first substrate holding hand can quickly be achieved with a simple arrangement. Thus, a direct transfer of the substrate from the first substrate holding hand to the second substrate holding hand, can be achieved at high speed with a low cost.
It is preferable that the first positioning mechanism comprises at least a pair of pins (71, 72) and that the positioning contact portion is disposed at the lateral surface of each of the pair of pins.
According to the arrangement above-mentioned, the first positioning mechanism has a very simple arrangement. That is, by contacting a substrate with the lateral surfaces (positioning contact portions) of a pair of pins, the substrate can be positioned on the first substrate holding hand. The adoption of such a simple arrangement can remarkably reduce the cost of the substrate transfer apparatus. When the first positioning mechanism has at least a pair of (two) pins, a substrate can successfully be positioned on the first substrate holding hand. However, the first positioning mechanism may have for example three or more pins.
The first substrate transfer mechanism may further comprise a regulating member (81xcx9c84) for regulating a relative movement of the substrate on the first substrate holding hand, and the first substrate transfer mechanism may be arranged to execute a positioning operation that the first substrate holding hand is moved to cause the substrate thereon to come in contact with the positioning contact portion and that the substrate is further relatively moved toward the regulating member on the first substrate holding hand, thereby to guide the substrate to a predetermined position on the first substrate holding hand.
According to the arrangement above-mentioned, the substrate can accurately be positioned, on the first substrate holding hand, within a predetermined positional range regulated by the regulating member.
The regulating member may be fixed onto the first substrate holding hand.
Preferably, a substrate is transferred from the first substrate holding hand to the second substrate holding hand after the substrate has been positioned on the first substrate holding hand. This securely achieves the transfer of the substrate from the first substrate holding hand to the second substrate holding hand.
The second substrate holding hand is preferably movable while holding a substrate, and there is preferably further disposed a second positioning mechanism (71, 72) disposed, in the moving passage of a substrate held by the second substrate holding hand, independently from the second substrate transfer mechanism, and having a positioning contact portion for regulating the movement of a substrate such that the substrate is positioned at a predetermined position on the second substrate holding hand.
According to the arrangement above-mentioned, a substrate can be positioned on the second substrate holding hand in a manner similar to that in which a substrate can be positioned on the first substrate holding hand. Thus, the transfer of a substrate by the second substrate holding hand can successfully be conducted without occurrence of defective transfer (falling of a substrate or the like). Further, a substrate can accurately be transferred from the second substrate transfer mechanism to the first substrate transfer mechanism.
It is preferable that the second positioning mechanism comprises at least a pair of pins (71, 72), and that the positioning contact portion is disposed at the lateral surface of each of the pair of pins.
According to the arrangement above-mentioned, the second positioning mechanism can be formed in a simple arrangement with a very low cost. When the second positioning mechanism has at least a pair of (two) pins, a substrate can sufficiently be positioned on the second substrate holding hand. However, the second positioning mechanism may have for example three or more pins.
The second substrate transfer mechanism preferably further comprises a regulating member (9194) for regulating a relative movement of a substrate on the second substrate holding hand, and the second substrate transfer mechanism is preferably arranged to execute a positioning operation that the second substrate holding hand is moved to cause the substrate thereon to come in contact with the positioning contact portion and that the substrate is further relatively moved toward the regulating member on the second substrate holding hand, thereby to guide the substrate to a predetermined position on the second substrate holding hand. According to the arrangement above-mentioned, the substrate can securely be positioned on the second substrate holding hand.
Preferably, a substrate is transferred from the second substrate holding hand to the first substrate holding hand after the substrate has been positioned on the second substrate holding hand. According to the arrangement above-mentioned, the transfer of a substrate from the second substrate holding hand to the first substrate holding hand can securely be executed.
The first positioning mechanism may share the positioning contact portion with the second positioning mechanism. According to the arrangement above-mentioned, the cost can further be reduced.
When there is determined a substrate transfer position (WT) to be used for transfer of a substrate between the first substrate holding hand and the second substrate holding hand, the positioning contact portion which is used in common by the first and second positioning mechanisms, is preferably disposed at a position either at the side of the first substrate holding hand or at the side of the second substrate holding hand with respect to this substrate transfer position. The first substrate transfer mechanism is preferably arranged to execute a positioning operation that the first substrate holding hand is moved from the substrate transfer position to the positioning contact portion, thereby to position the substrate at a predetermined position on the first substrate holding hand, and the second substrate transfer mechanism is preferably arranged to execute a positioning operation that the second substrate holding hand is moved from the substrate transfer position to the positioning contact portion, thereby to position the substrate at a predetermined position on the second substrate holding hand.
According to the arrangement above-mentioned, when each of the first and second substrate holding hands is moved from the substrate transfer position to the positioning contact portion, the substrate thereon can be positioned at a predetermined position. Thus, the same substrate transfer position can be set for transferring a substrate from the first substrate transfer mechanism to the second substrate transfer mechanism and for transferring a substrate from the second substrate transfer mechanism to the first substrate transfer mechanism. Further, the positioning contact portion used for positioning a substrate can commonly be used for positioning a substrate on the first substrate holding hand and for positioning a substrate on the second substrate holding hand. This is advantageous in view of cost reduction.
According to the present invention, a substrate transfer method comprises: a step of holding a substrate by a first substrate holding hand of a first substrate transfer mechanism (IR); and a step of positioning the substrate at a predetermined position on the first substrate holding hand by moving the first substrate holding hand which holds the substrate, while regulating the movement of the substrate by a positioning contact portion (71, 72) disposed independently from the first substrate transfer mechanism. This substrate transfer method further comprises a step of transferring, after the positioning step above-mentioned, the substrate from the first substrate holding hand of the first substrate transfer mechanism to a second substrate holding hand of a second substrate transfer mechanism.
A method according to an embodiment of the present invention further comprises: a step of holding a substrate by the second substrate holding hand of the second substrate transfer mechanism (CR); a step of positioning the substrate at a predetermined position on the second substrate holding hand by moving the second substrate holding hand which holds the substrate, while regulating the movement of the substrate by a positioning contact portion (71, 72) disposed independently from the second substrate transfer mechanism; and a step of transferring, after this positioning step, the substrate from the second substrate holding hand to the first substrate holding hand.
According to the method above-mentioned, a substrate is previously positioned prior to its transfer not only from the first substrate holding hand to the second substrate holding hand, but also from the second substrate holding hand to the first substrate holding hand. Thus, the substrate can securely be transferred. As above-mentioned, provision may be made such that the positioning contact portion is used for bi-directional transfers of the substrate. This prevents the cost from being increased.